Endothelial Regulation of Pulmonary Vascular Tone

Abstract

This chapter focuses on the central significance of the pulmonary endothelium in the control of pulmonary vascular tone in pulmonary development, homeostasis, and pathophysiological processes. We review the upstream stimuli known to regulate the expression and activity of endothelium-specific mediators of vascular tone. Subsequently, we focus on the known actions of the endothelium-derived vasoactive effectors most important for the balance of control of vasomotor tone – vasodilators (nitric oxide and prostacyclin) and vasoconstrictors (thromoboxane A2 and endothelin). Additional mediators that may affect pulmonary vasomotor tone and endothelium-derived hyperpolarizing factor related activity are discussed, along with more poorly characterized effectors. Finally, the complex balance of these vasoactive factors and the intersection of their downstream signaling pathways is presented in the context of prototypical in vivo physiological and pathophysiological processes in the pulmonary circulation.